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Voltammetric Behavior and Determination of Trace Amounts of Omeprazole Using an Edge-plane Pyrolytic Graphite Electrode.

Shahrokhian S, Ghalkhani M, Bayat M, Ghorbani-Bidkorbeh F - Iran J Pharm Res (2015)

Bottom Line: The voltammetric performance of edge-plane pyrolytic graphite (EPG) electrode via adsorptive stripping voltammetry was investigated for study of the electrochemical behavior of omeprazole (OMZ) in aqueous solution.The results revealed that the oxidation of OMZ is an irreversible pH-dependent process that proceeds with the transfer of one electron and one proton in an adsorption-controlled mechanism.Simplicity, high reproducibility and low detection limit (3 nM) of the electrode response as well as wide linear range (0.01 to 4.0 µM) can be stated as significant features of this electrode.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Sharif University of Technology, Tehran, Iran . ; Institute for Nanoscience and Technology, Sharif University of Technology, Tehran, Iran .

ABSTRACT
The voltammetric performance of edge-plane pyrolytic graphite (EPG) electrode via adsorptive stripping voltammetry was investigated for study of the electrochemical behavior of omeprazole (OMZ) in aqueous solution. The results revealed that the oxidation of OMZ is an irreversible pH-dependent process that proceeds with the transfer of one electron and one proton in an adsorption-controlled mechanism. The determination conditions, such as the pH values of the supporting electrolyte, accumulation time and scan rate were optimized. Simplicity, high reproducibility and low detection limit (3 nM) of the electrode response as well as wide linear range (0.01 to 4.0 µM) can be stated as significant features of this electrode. The EPG electrode was successfully applied for the determination of OMZ in pharmaceutical formulations and satisfactory results were obtained.

No MeSH data available.


Related in: MedlinePlus

The plot of peak current (μA) versus accumulation time (s) of 1 μM of OMZ at the EPG electrode in 0.1 M phosphate buffer solution (pH 7.0).
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Figure 5: The plot of peak current (μA) versus accumulation time (s) of 1 μM of OMZ at the EPG electrode in 0.1 M phosphate buffer solution (pH 7.0).

Mentions: Accumulation step is usually a simple and effective way to enhance the sensitivity of the determination. Upon OMZ adsorption on the EPG electrode, application of a preconcentration step to increase the electrochemical response and also the sensitivity is necessary. Therefore, the accumulation of OMZ on the electrode surface, under open circuit, was performed before electrochemical measurements. As for any technique employing preconcentration step, the accumulation time is of significant importance for the voltammetric signal. Results show that the longer accumulation times to 500 s, increase the amount of adsorbed OMZ and therefore give higher peak current. Then, the peak currents remain constant due to the surface saturation (Figure 4). As the OMZ concentration decreases, it takes a longer accumulation time to reach the saturation peak current. A smaller peak current is obtained when a shorter accumulation time is used. A comprise between sensitivity and analysis time has to be considered. Taking account of sensitivity and efficiency and also response repeatability, the accumulation time was set at 500 s as a reasonable comprise in the analytical measurements.


Voltammetric Behavior and Determination of Trace Amounts of Omeprazole Using an Edge-plane Pyrolytic Graphite Electrode.

Shahrokhian S, Ghalkhani M, Bayat M, Ghorbani-Bidkorbeh F - Iran J Pharm Res (2015)

The plot of peak current (μA) versus accumulation time (s) of 1 μM of OMZ at the EPG electrode in 0.1 M phosphate buffer solution (pH 7.0).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4403062&req=5

Figure 5: The plot of peak current (μA) versus accumulation time (s) of 1 μM of OMZ at the EPG electrode in 0.1 M phosphate buffer solution (pH 7.0).
Mentions: Accumulation step is usually a simple and effective way to enhance the sensitivity of the determination. Upon OMZ adsorption on the EPG electrode, application of a preconcentration step to increase the electrochemical response and also the sensitivity is necessary. Therefore, the accumulation of OMZ on the electrode surface, under open circuit, was performed before electrochemical measurements. As for any technique employing preconcentration step, the accumulation time is of significant importance for the voltammetric signal. Results show that the longer accumulation times to 500 s, increase the amount of adsorbed OMZ and therefore give higher peak current. Then, the peak currents remain constant due to the surface saturation (Figure 4). As the OMZ concentration decreases, it takes a longer accumulation time to reach the saturation peak current. A smaller peak current is obtained when a shorter accumulation time is used. A comprise between sensitivity and analysis time has to be considered. Taking account of sensitivity and efficiency and also response repeatability, the accumulation time was set at 500 s as a reasonable comprise in the analytical measurements.

Bottom Line: The voltammetric performance of edge-plane pyrolytic graphite (EPG) electrode via adsorptive stripping voltammetry was investigated for study of the electrochemical behavior of omeprazole (OMZ) in aqueous solution.The results revealed that the oxidation of OMZ is an irreversible pH-dependent process that proceeds with the transfer of one electron and one proton in an adsorption-controlled mechanism.Simplicity, high reproducibility and low detection limit (3 nM) of the electrode response as well as wide linear range (0.01 to 4.0 µM) can be stated as significant features of this electrode.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Sharif University of Technology, Tehran, Iran . ; Institute for Nanoscience and Technology, Sharif University of Technology, Tehran, Iran .

ABSTRACT
The voltammetric performance of edge-plane pyrolytic graphite (EPG) electrode via adsorptive stripping voltammetry was investigated for study of the electrochemical behavior of omeprazole (OMZ) in aqueous solution. The results revealed that the oxidation of OMZ is an irreversible pH-dependent process that proceeds with the transfer of one electron and one proton in an adsorption-controlled mechanism. The determination conditions, such as the pH values of the supporting electrolyte, accumulation time and scan rate were optimized. Simplicity, high reproducibility and low detection limit (3 nM) of the electrode response as well as wide linear range (0.01 to 4.0 µM) can be stated as significant features of this electrode. The EPG electrode was successfully applied for the determination of OMZ in pharmaceutical formulations and satisfactory results were obtained.

No MeSH data available.


Related in: MedlinePlus